RESUMO
Due to the inflow of meltwater from the Midre Lovénbreen glacier upstream of Kongsfjorden, the nutrient concentration of Kongsfjorden change from the estuary to the interior of the fjord. Our objective was to explore the changes in bacterial community structure and metabolism-related genes from the estuary to fjord by metagenomic analysis. Our data indicate that glacial meltwater input has altered the physicochemical properties of the fjords, with a significant effect, in particular, on fjords salinity, thus altering the relative abundance of some specific bacterial groups. In addition, we suggest that the salinity of a fjord is an important factor affecting the abundance of genes associated with the nitrogen and sulfur cycles in the fjord. Changes in salinity may affect the relative abundance of microbial populations that carry metabolic genes, thus affecting the relative abundance of genes associated with the nitrogen and sulfur cycles.
Assuntos
Bactérias , Estuários , Metagenômica , Salinidade , Bactérias/genética , Bactérias/classificação , Bactérias/efeitos dos fármacos , Bactérias/isolamento & purificação , Regiões Árticas , Microbiota , Camada de Gelo/microbiologia , Variação Genética , Biodiversidade , Metagenoma , Enxofre/metabolismo , Nitrogênio/metabolismo , FilogeniaRESUMO
Antarctic seaweeds are vital components of polar marine ecosystems, playing a crucial role in nutrient cycling and supporting diverse life forms. The sulfur content in these organisms is particularly interesting due to its implication in biogeochemical processes and potential impacts on local and global environmental systems. In this study, we present a comprehensive characterization of seaweed collected in the Antarctic in terms of their total sulfur content and its distribution among different classes of species, including thiols, using various methods and high-sensitivity techniques. The data presented in this paper are unprecedented in the scientific literature. These methods allowed for the determination of total sulfur content and the distribution of sulfur compounds in different fractions, such as water-soluble and proteins, as well as the speciation of sulfur compounds in these fractions, providing valuable insights into the chemical composition of these unique marine organisms. Our results revealed that the total sulfur concentration in Antarctic seaweeds varied widely across different species, ranging from 5.5 to 56 g kg-1 dry weight. Furthermore, our investigation into the sulfur speciation revealed the presence of various sulfur compounds, including sulfate, and some thiols, which were quantified in all ten seaweed species evaluated. The concentration of these individual sulfur species also displayed considerable variability among the studied seaweeds. This study provides the first in-depth examination of total sulfur content and sulfur speciation in brown and red Antarctic seaweeds.
Assuntos
Alga Marinha , Alga Marinha/química , Regiões Antárticas , Peso Molecular , Ecossistema , Enxofre/metabolismo , Compostos de Enxofre/metabolismo , Verduras , Compostos de Sulfidrila/metabolismoRESUMO
Fungal pathogens are a major cause of death, especially among immunocompromised patients. Therapies against invasive fungal infections are restricted to a few antifungals; therefore, novel therapies are necessary. Nutritional signaling and regulation are important for pathogen establishment in the host. In Cryptococcus neoformans, the causal agent of fungal meningitis, amino acid uptake and biosynthesis are major aspects of nutritional adaptation. Disruptions in these pathways lead to virulence attenuation in an animal model of infection, especially for sulfur uptake and sulfur amino acid biosynthesis. Deletion of Cys3, the main transcription factor that controls these pathways, is the most deleterious gene knockout in vitro and in vivo, making it an important target for further application. Previously, we demonstrated that Cys3 is part of a protein complex, including calcineurin, which is necessary to maintain high Cys3 protein levels during sulfur uptake and sulfur amino acid biosynthesis. In the current study, other aspects of Cys3 regulation are explored. Two lines of evidence suggest that C. neoformans Cys3 does not interact with the F-box WD40 protein annotated as Met30, indicating another protein mediates Cys3 ubiquitin degradation. However, we found another level of Cys3 regulation, which involves protein interactions between Cys3 and ATP sulfurylase (MET3 gene). We show that an atypical leucine zipper at the N-terminus of ATP sulfurylase is essential for physical interaction with Cys3 and calcineurin. Our data suggests that Cys3 and ATP sulfurylase interact to regulate Cys3 transcriptional activity. This work evidences the complexity involved in the regulation of a transcription factor essential for the sulfur metabolism, which is a biological process important to nutritional adaptation, oxidative stress response, nucleic acid stability, and methylation. This information may be useful in designing novel therapies against fungal infections.
Assuntos
Aminoácidos Sulfúricos , Criptococose , Cryptococcus neoformans , Animais , Calcineurina/metabolismo , Zíper de Leucina , Sulfato Adenililtransferase/metabolismo , Fatores de Transcrição/metabolismo , Criptococose/microbiologia , Aminoácidos Sulfúricos/metabolismo , Enxofre/metabolismo , Proteínas Fúngicas/metabolismoRESUMO
The transsulfuration pathway (TSP) is a metabolic pathway involving sulfur transfer from homocysteine to cysteine. Transsulfuration pathway leads to many sulfur metabolites, principally glutathione, H2S, taurine, and cysteine. Key enzymes of the TSP, such as cystathionine ß-synthase and cystathionine γ-lyase, are essential regulators at multiple levels in this pathway. TSP metabolites are implicated in many physiological processes in the central nervous system and other tissues. TSP is important in controlling sulfur balance and optimal cellular functions such as glutathione synthesis. Alterations in the TSP and related pathways (transmethylation and remethylation) are altered in several neurodegenerative diseases, including Parkinson's disease, suggesting their participation in the pathophysiology and progression of these diseases. In Parkinson's disease many cellular processes are comprised mainly those that regulate redox homeostasis, inflammation, reticulum endoplasmic stress, mitochondrial function, oxidative stress, and sulfur content metabolites of TSP are involved in these damage processes. Current research on the transsulfuration pathway in Parkinson's disease has primarily focused on the synthesis and function of certain metabolites, particularly glutathione. However, our understanding of the regulation of other metabolites of the transsulfuration pathway, as well as their relationships with other metabolites, and their synthesis regulation in Parkinson´s disease remain limited. Thus, this paper highlights the importance of studying the molecular dynamics in different metabolites and enzymes that affect the transsulfuration in Parkinson's disease.
Assuntos
Cisteína , Doença de Parkinson , Humanos , Cisteína/metabolismo , Enxofre/metabolismo , Cistationina beta-Sintase/metabolismo , Glutationa/metabolismoRESUMO
The recent revision of the Acidithiobacillia class using genomic taxonomy methods has shown that, in addition to the existence of previously unrecognized genera and species, some species of the class harbor levels of divergence that are congruent with ongoing differentiation processes. In this study, we have performed a subspecies-level analysis of sequenced strains of Acidithiobacillus ferrooxidans to prove the existence of distinct sublineages and identify the discriminant genomic/genetic characteristics linked to these sublineages, and to shed light on the processes driving such differentiation. Differences in the genomic relatedness metrics, levels of synteny, gene content, and both integrated and episomal mobile genetic elements (MGE) repertoires support the existence of two subspecies-level taxa within A. ferrooxidans. While sublineage 2A harbors a small plasmid related to pTF5, this episomal MGE is absent in sublineage 2B strains. Likewise, clear differences in the occurrence, coverage and conservation of integrated MGEs are apparent between sublineages. Differential MGE-associated gene cargo pertained to the functional categories of energy metabolism, ion transport, cell surface modification, and defense mechanisms. Inferred functional differences have the potential to impact long-term adaptive processes and may underpin the basis of the subspecies-level differentiation uncovered within A. ferrooxidans. Genome resequencing of iron- and sulfur-adapted cultures of a selected 2A sublineage strain (CCM 4253) showed that both episomal and large integrated MGEs are conserved over twenty generations in either growth condition. In turn, active insertion sequences profoundly impact short-term adaptive processes. The ISAfe1 element was found to be highly active in sublineage 2A strain CCM 4253. Phenotypic mutations caused by the transposition of ISAfe1 into the pstC2 encoding phosphate-transport system permease protein were detected in sulfur-adapted cultures and shown to impair growth on ferrous iron upon the switch of electron donor. The phenotypic manifestation of the â³pstC2 mutation, such as a loss of the ability to oxidize ferrous iron, is likely related to the inability of the mutant to secure the phosphorous availability for electron transport-linked phosphorylation coupled to iron oxidation. Depletion of the transpositional â³pstC2 mutation occurred concomitantly with a shortening of the iron-oxidation lag phase at later transfers on a ferrous iron-containing medium. Therefore, the pstII operon appears to play an essential role in A. ferrooxidans when cells oxidize ferrous iron. Results highlight the influence of insertion sequences and both integrated and episomal mobile genetic elements in the short- and long-term adaptive processes of A. ferrooxidans strains under changing growth conditions.
Assuntos
Acidithiobacillus , Elementos de DNA Transponíveis , Elementos de DNA Transponíveis/genética , Acidithiobacillus/genética , Acidithiobacillus/metabolismo , Ferro/metabolismo , Enxofre/metabolismo , OxirreduçãoRESUMO
LSUs (RESPONSE TO LOW SULFUR) are plant-specific proteins of unknown function that were initially identified during transcriptomic studies of the sulfur deficiency response in Arabidopsis. Recent functional studies have shown that LSUs are important hubs of protein interaction networks with potential roles in plant stress responses. In particular, LSU proteins have been reported to interact with members of the brassinosteroid, jasmonate signaling, and ethylene biosynthetic pathways, suggesting that LSUs may be involved in response to plant stress through modulation of phytohormones. Furthermore, in silico analysis of the promoter regions of LSU genes in Arabidopsis has revealed the presence of cis-regulatory elements that are potentially responsive to phytohormones such as ABA, auxin, and jasmonic acid, suggesting crosstalk between LSU proteins and phytohormones. In this review, we summarize current knowledge about the LSU gene family in plants and its potential role in phytohormone responses.
Assuntos
Arabidopsis , Reguladores de Crescimento de Plantas , Reguladores de Crescimento de Plantas/genética , Reguladores de Crescimento de Plantas/metabolismo , Arabidopsis/genética , Arabidopsis/metabolismo , Ácidos Indolacéticos/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Enxofre/metabolismo , Regulação da Expressão Gênica de Plantas , Estresse Fisiológico/genéticaRESUMO
The soil bacterium Pseudomonas putida KT2440 has been shown to produce selenium nanoparticles aerobically from selenite; however, the molecular actors involved in this process are unknown. Here, through a combination of genetic and analytical techniques, we report the first insights into selenite metabolism in this bacterium. Our results suggest that the reduction of selenite occurs through an interconnected metabolic network involving central metabolic reactions, sulphur metabolism, and the response to oxidative stress. Genes such as sucA, D2HGDH and PP_3148 revealed that the 2-ketoglutarate and glutamate metabolism is important to convert selenite into selenium. On the other hand, mutations affecting the activity of the sulphite reductase decreased the bacteria's ability to transform selenite. Other genes related to sulphur metabolism (ssuEF, sfnCE, sqrR, sqr and pdo2) and stress response (gqr, lsfA, ahpCF and sadI) were also identified as involved in selenite transformation. Interestingly, suppression of genes sqrR, sqr and pdo2 resulted in the production of selenium nanoparticles at a higher rate than the wild-type strain, which is of biotechnological interest. The data provided in this study brings us closer to understanding the metabolism of selenium in bacteria and offers new targets for the development of biotechnological tools for the production of selenium nanoparticles.
Assuntos
Nanopartículas , Pseudomonas putida , Selênio , Pseudomonas putida/genética , Pseudomonas putida/metabolismo , Selênio/metabolismo , Nanopartículas/metabolismo , Ácido Selenioso/metabolismo , Estresse Oxidativo , Enxofre/metabolismoRESUMO
Soil contamination caused by improper waste disposal can affect plant growth. Tropical forage plants have rapid growth, high biomass production and vigorous regrowth. Chromium (Cr) is one of the most common contaminants in the environment. Sulfur (S) is a nutrient involved in various cell detoxification processes. The objective was to assess the effects of excess Cr on biomass production and concentrations of this metal, S and cationic micronutrients, under conditions of varying supply of S for Tanzania guinea grass. The experiment was conducted in randomized complete blocks in a 3 × 4 factorial scheme, corresponding to three levels of S (0.1, 1.9 and 3.7 mmol L-1) and four levels of Cr (0.0, 0.5, 1.0 and 2.0 mmol L-1) in three replicates. Root surface area, shoot and root biomass production, concentrations of total S, sulfate-S, Cr and cationic micronutrients, and Cr transport factor were determined. S level of 1.9 mmol L-1 reduced the toxicity by Cr in Tanzania guinea grass, expressed by the higher shoot and root dry weight production, greater stability in the cellular concentration of sulfate-S and higher concentrations of micronutrients. It was concluded that the high availability of S reduced the toxicity by Cr(VI) in Tanzania guinea grass, expressed by the higher shoot and root dry weight production, greater stability in the cellular concentration of sulfate-S and higher concentration of micronutrients in the grass shoots.
Assuntos
Cromo , Poluentes do Solo , Cromo/toxicidade , Cromo/análise , Tanzânia , Biomassa , Micronutrientes , Guiné , Poaceae/metabolismo , Enxofre/metabolismo , Raízes de Plantas/metabolismo , Poluentes do Solo/análiseRESUMO
Bioleaching of metal sulfides is performed by diverse microorganisms. The dissolution of metal sulfides occurs via two chemical pathways, either the thiosulfate or the polysulfide pathway. These are determined by the metal sulfides' mineralogy and their acid solubility. The microbial cell enables metal sulfide dissolution via oxidation of iron(II) ions and inorganic sulfur compounds. Thereby, the metal sulfide attacking agents iron(III) ions and protons are generated. Cells are active either in a planktonic state or attached to the mineral surface, forming biofilms. This review, as an update of the previous one (Vera et al., 2013a), summarizes some recent discoveries relevant to bioleaching microorganisms, contributing to a better understanding of their lifestyle. These comprise phylogeny, chemical pathways, surface science, biochemistry of iron and sulfur metabolism, anaerobic metabolism, cell-cell communication, molecular biology, and biofilm lifestyle. Recent advances from genetic engineering applied to bioleaching microorganisms will allow in the future to better understand important aspects of their physiology, as well as to open new possibilities for synthetic biology applications of leaching microbial consortia. KEY POINTS: ⢠Leaching of metal sulfides is strongly enhanced by microorganisms ⢠Biofilm formation and extracellular polymer production influences bioleaching ⢠Cell interactions in mixed bioleaching cultures are key for process optimization.
Assuntos
Prótons , Tiossulfatos , Compostos Férricos , Metais/metabolismo , Sulfetos/metabolismo , Ferro/metabolismo , Minerais , Enxofre/metabolismo , Polímeros , Compostos FerrososRESUMO
PURPOSE: This study aimed to assess the possible healing effect of combination treatment with a hydrogen sulfide (H2S) donor, sodium hydrosulfide (NaHS) plus tadalafil on partial bladder outlet obstruction (PBOO)-induced bladder dysfunction. MATERIALS AND METHODS: A total of 75 male Sprague-Dawley rats aged 10-wk and 300-350g were divided into five groups; control; PBOO; PBOO+NaHS (5.6mg/kg/day, i.p., 6-wk); PBOO+tadalafil (2mg/kg/day, oral, 6-wk) and PBOO+NaHS+tadalafil. PBOO was created by partial urethral ligation. 6 weeks after obstruction, the in vitro contractile responses of the detrusor muscle and Western blotting, H2S and malondialdehyde assay were performed in bladder tissues. RESULTS: There was an increase in bladder weight(p<0.001) and a decrease in contractile responses to KCL(p<0.001), carbachol(p<0.01), electrical field stimulation(p<0.05) and ATP (p<0.001) in the detrusor smooth muscle of obstructed rats which was normalized after the combination treatment. Cystathionine γ-lyase and cystathionine ß-synthase, and nuclear factor kappa B protein levels did not significantly differ among groups. The obstruction induced decrement in 3-mercaptopyruvate sulfur transferase protein expression(p<0.001) and H2S levels(p<0.01) as well as increment in protein expressions of neuronal nitric oxide synthase (NO, p<0.001), endothelial NOS (p<0.05), inducible NOS(p<0.001), hypoxia-inducible factor 1-alpha (p<0.01), and malondialdehyde levels (p<0.01), when combined treatment entirely normalized. CONCLUSIONS: Combination therapy has beneficial effects on bladder dysfunction via regulating both H2S and nitric oxide pathways as well as downregulation of oxidative stress and hypoxia. The synergistic effect of H2S and nitric oxide is likely to modulate bladder function, which supports the combined therapy for enhancing clinical outcomes in men with BPH/LUTS.